Audio Engineering Associates KU4 Quick Manual
- Type
- Quick Manual
The Legacy of the RCA KU3A
The KU4 celebrates the legendary RCA unidirectional KU3A, a high-
sensitivity microphone designed for the Hollywood movie studios. Also
known as a M-10001 for its manufacturing number, it was RCA’s most
expensive ribbon microphone. Fewer than 600 were ever manufactured.
What made the KU3A special? It combined the smooth ribbon sound of
a 44 with a unidirectional pattern, a wide sweet spot and less proximity
bass boost. It expanded an engineer’s range of placement choices and
became a standard at film studios around the world.
Although condenser mics became the new standard by the end of
the 1960s, ribbon mics are still appreciated today by experienced
music recording engineers. However the KU3A is a rare microphone,
a collector’s item, and few studios or rental houses own them.
Opportunities to work with a good KU3A are limited.
We are proud to expand your opportunities with the AEA KU4 featuring an
RCA ribbon, interchangeable KU3A parts and consistent performance.
Contemporary realization of the RCA KU3A classic
• Supercardioid pattern for excellent rear rejection
• Reduced proximity effect
• Smooth, high-bandwidth frequency response
• Authentic New Old Stock RCA ribbon material
• High-quality anodized & nickel-plated finish
• Custom AEA transformer, neodymium magnets
• Consistent Quality
• Field-tech replaceable ribbon assembly
• Hand-crafted in Pasadena, California
How is the KU4 different from other ribbon microphones?
The KU4’s supressed rear lobe is useful when the back of a figure-of-eight would pick up undesirable sounds. The
KU4’s reduced proximity bass boost facilitates closer micing and its low-tuned ribbon delivers solid, undistorted bass.
These characteristics make the KU4 well suited for modern studio production.
Its lightly-tensioned, ultra low mass ribbon has a frequency response out to 40 kHz and fast, accurate transients.
There is no upper midrange ringing common to large condenser mics. The KU4’s ribbon is well protected and its
field-tech replaceable pole piece and ribbon assembly is a real convenience if an accident occurs.
The KU4 is your ticket to discovering why the KU3A has been part of high-end studio life for over 60 years. AEA is
honored to play a part in its history, and invites you to listen to the KU4 and claim your part of this legacy.
Audio Engineering Associates
KU4
Unidirectional Ribbon
Specifications:
Operating Principle: Velocity microphone
Frequency Response: Below 30 Hz to above 20 kHz
Maximum SPL: 140 + dB SPL above 200Hz for 1% third harmonic
Output Sensitivity: 2.8 mV/Pa into unloaded circuit
Output Impedance: 300 Ω nominal
Recommended Load: 1.2 KΩ or greater
Phantom power: Not required or recommended
Polarity: Pin 2 high for positive pressure at the front of the microphone.
Connector: XLR-3M wired to a 1.5 meter captive cable
Off Axis Response:
Polar Pattern: Supercardioid
Relative Output at 180° (dB): -12
Angle of Maximum Rejection: 135°
Transducer element
Ribbon Thickness: 1.8 microns ( .0000018 meter ) of pure aluminum
Ribbon Width: 0.082” (2.1 mm)
Ribbon Length: 1.25” (28.6 mm)
Accessories:
Included: Custom storage/shipping case, stand adapter, manual and
attached 1.5 meter microphone cable
Limited Warranty:
Three years parts and labor, shipping not included.
Displayed range from 200 Hz up due to measurement room size limitations.
0 dBr = 2.8 mv / Pa
Manufactured by Audio Engineering Associates:
1029 N. Allen Ave. Pasadena, California 91104, USA
Tel: +626-798-9128 Fax: +626-798-2378 www.ribbonmics.com
For more information contact:
KU4 weight with cable: 4.7 pounds (2.15 kg)
KU4 weight with case: 7 pounds (3.2 kg)
Length: 12.65” (32.4 cm) Width: 4.62” (11.7 cm)
Depth: 3.75”(9.5 cm)
Options
M Hand tuning to stereo match a pair
Accessories
B Gray twill zippered bag
AD-1 5/8”-27 F stand adapter to 1/2-NPS M
44VC Vertical carry case for one
44VC-2 Vertical carry case for two
4.6”
3.7”
12.6”
KU4 Frequency Response to 40 kHz
Frequency
Output Voltage (dBr)
0
-6
-12
-18
-24
-30
dB
30°
60°
90°
120°
150°
180°
210°
240°
270°
300°
330°
200Hz
500Hz
1000Hz
2000Hz
5000Hz
7000Hz
10000Hz
AEA KU4 Polar Response
-
1
-
2
